Current collector holder for a carbon shoe

ABSTRACT

A current collector holder for a carbon shoe, which bears against a contact wire, for electrically driven vehicles, has two first webs which grip a foot region of the shoe, and two second webs which project away from the shoe are arranged underneath the shoe. An independent spring system is provided for exerting forces against the second webs for pressing the first webs against the foot region of the shoe. The spring system has a spring which extends uniformly in the longitudinal direction of the shoe, and bears with its longitudinal regions against the second webs to transmit a spring force, acting in a direction transverse to the shoe, to the second webs. The holder is simple to construct and provides contact forces acting continuously over the entire length of the shoe.

BACKGROUND OF THE INVENTION

The invention relates to a current collector holder for a carbon shoe,which bears against a contact wire, for electrically driven vehicles,which holder has two first webs, which grip the foot region of the shoe,and two second webs, which project away from the shoe and are arrangedunderneath it, a separate spring system being provided which presses thesecond webs relatively towards one another and hence presses the firstwebs against the foot region of the shoe.

As a rule, the holder is connected to the current collector via sideelements, so-called horns.

In the case of a known holder of this type (DD-PS 159,163), the springsystem is formed by a plurality of spiral springs which act on thesecond webs at discrete points on the second webs, oriented transverselywith respect to the longitudinal direction of the shoe. Thisconstruction is relatively complicated and its mass is very high. Inaddition, the forces do not act continuously over the entire length ofthe second webs, as a result of which stresses are caused in the carbonshoe. At the same time, the contact voltage drop between the carbon shoeand the holder is relatively high.

SUMMARY OF THE INVENTION

The invention is based on the object of constructing the holdermentioned initially in such a manner that it is simpler than that knownand in such a manner that the spring forces act continuously over theentire length of the shoe.

This construction is achieved according to the invention in that aspring is provided as the spring system, which spring extends unchangedin the longitudinal direction of the shoe, bears against the second webswith longitudinal regions, and in this way transmits its spring force,which acts in the transverse direction of the shoe, to the second webs.

This construction is distinguished by simplicity. This has a favorableeffect on production and allows the use of worn carbon shoes in a simplemanner. In addition, the spring acts continuously over the entire lengthof the second webs. This leads to it being possible to hold the carbonshoes with forces which remain constant in the longitudinal direction,in a manner which is simpler than in the known case, which, as a resultof the specific brittleness of the carbon shoe, is better than retentionof the same with forces which act differently in the longitudinaldirection. In addition, the electrical contact resistance from thecarbon shoe to the holder is then constant and smaller over the entireshoe.

It should be mentioned that it is already known for carbon shoes to beheld with forces which act continuously in the longitudinal direction.Thus, it is known (AT-PS 209,376) for rubber strips to be providedbetween the first webs and the carbon shoe. The surfaces separated bythe rubber strips do not contribute to making electrical contact. Therubber strips are subject to severe ageing effects. In addition, it ispossible to transmit and produce only limited forces using these rubberstrips. Furthermore, it is known (AT-PS 342,117 and DE-OS 2,138,459) forthe holder itself to be constructed in a sprung manner in specificregions in order to produce the retention forces for the carbon shoe.For this reason, it is not possible to take optimal account of allsituations in this way, as in the case of the solution according to theinvention in which the holder and spring system are separate from oneanother.

A development of the invention is for the spring to form an open figurein the transverse direction of the shoe, which figure is curved on oneside, has two mutually opposite edges, grips the second webs and pressesthem against one another. In the case of shoes which are benttransversely with respect to the contact wire, the spring isadditionally provided with the radius of the holder. However, it is alsopossible for the spring to be provided with transverse slots which endshortly in front of the edges.

At the ends, the spring may have holes into which hooks can be inserted,by means of which the springs can be pulled out of the shoe.

Another possibility is for the spring to be a leaf spring which isslightly curved in the transverse direction of the shoe, is arrangedbetween the second webs and presses the latter apart.

It is furthermore possible for the spring to form a closed figure in thetransverse direction of the shoe, which figure is curved on one side, isarranged between the second webs and presses the latter apart.

The spring of this type can be hollow inside, but it can also be solidinternally and be composed of strongly elastic material.

If the spring is hollow, then the spring wall could be constructedelastically, there being compressed gas, especially compressed air, inits interior in a controlled manner.

It is naturally expedient if the springs as claimed in claims 1 to 7 arecomposed of spring steel.

It is furthermore proposed that the first webs be connected to oneanother via a wall which is arranged underneath the second webs. Theholder without a spring is then integral. If the first webs are notconnected to a wall, then the holder without a spring comprises twohalves.

An alternative to the second webs which extend over the entire holderlength is for said webs to be short pieces in the longitudinaldirection, which short pieces are connected to the first webs on theright and left alternately and interlock. In this case, the holderwithout a spring comprises two parts. If the first webs are connected toa wall underneath the second webs, then the holder is integral.

It is thus expedient if the second webs have laterally projectingshoulders at their free ends, behind which shoulders the spring engages.

It is furthermore proposed that, in the longitudinal direction of theshoe, the spring comprises a plurality of pieces which are adjacent toone another, with or without a space. This construction is particularlyinteresting if the shoe is bent transversely with respect to the contactwire.

A further construction of the invention is for a sensing element, whichrecords the mechanical oscillations of the shoe, to be located on theholder. This sensing element is connected to an indicating apparatus. Inthis way is it possible to detect defects of the most varied type, forexample defects of the carbon shoe, such as delaminations in the regionof the sliding surface of the carbon shoe, or shoe fractures, as well asdefects in the contact wire. If everything is serviceable, theindicating apparatus indicates a specific mechanical behavior of thesensing element and hence of the shoe. Defects of the said type lead todeviations from this indication.

If the first webs are connected to one another via a wall which isarranged underneath the second webs, then it is expedient to arrange thesensing element in the space above this wall.

It is furthermore expedient to provide two springs, between which thesensing element is located.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the invention result from the drawings, in which:

FIG. 1 shows a section through a first embodiment of the invention, inaccordance with the line I--I in FIG. 2,

FIG. 1a illustrates a variation of the embodiment of FIG. 1 in which thespring is in a closed configuration,

FIG. 2 shows a view of the first embodiment from underneath, without aspring,

FIG. 2A illustrates the embodiment of the invention shown by FIG. 2 inwhich the spring is formed from a plurality of adjacent pieces,

FIG. 3 shows a section through a second embodiment corresponding to FIG.1,

FIG. 4 shows a section through a third embodiment of the inventioncorresponding to FIG. 1,

FIG. 4A shows a section through the embodiment of the inventionillustrated by FIG. 4, taken along directional lines X--X, illustratinga sensing element,

FIG. 5 shows a perspective view of a spring,

FIG. 6 shows a further embodiment before assembly, and FIG. 7 afterassembly,

FIG. 8 and FIG. 8A illustrate, respectively, a spring having an upwardlyprojecting bulge illustrated in perspective, and a sectional view of adevice in accordance with the present invention in which said springhaving said upwardly projecting bulge is in an operative position inwhich the bulge presses a contact strip inserted between a carbon shoeand a holder against the carbon shoe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

In FIGS. 1 and 2, 1 designates a carbon shoe, 2 a holder for said carbonshoe, comprising the parts 2a and 2b, and 3 a leaf spring. The holderhas first webs 4 which grip a foot region 5 of the carbon shoe.Furthermore, the holder has two webs 6 which have inwardly projectingshoulders 7 at their free ends. Said shoulders 7 are used as retentionfor the spring 3. The latter is bent slightly in the transversedirection of the shoe and exerts a pressure on the webs 6 which leads tothe webs 4 firmly gripping the foot region 5 of the carbon shoe 1. Ifthe spring 3 is pulled out vertically with respect to the plane of thedrawing in FIG. 1, then, inter alia, the two parts 2a and 2b aredetached from one another. FIG. 1a illustrates an embodiment similar tothat of FIG. 1 in which the leaf spring 3 of FIG. 1 is replaced by aclosed spring 3A illustrated in FIG. 1a. FIG. 2A illustrates anembodiment of the invention similar to that shown in FIG. 2 except FIG.2A illustrates that the spring element is formed from a plurality ofseparate, adjacent pieces 22, 24, 26 and 28.

The embodiment in FIG. 3 differs from the embodiment in FIGS. 1 and 2essentially in that the carbon shoe 1 has an inwardly expanding section10 in the central region, into which first webs 14 engage. Otherwise,this embodiment corresponds to the embodiment in FIGS. 1 and 2.

In the case of the embodiment in FIG. 4, the holder 16 is integral. Ithas first webs 4 and second webs 6. Otherwise, a wall 17 is providedwhich connects the webs 4 to one another, runs underneath the webs 6 andforms a space in which the webs 6 and a spring 18 are located. Saidspring 18 is bent transversely with respect to the longitudinaldirection of the shoe and presses the second webs 6 against one another.In this way, the first webs 4 are also pressed against one another. Tothis extent, they hold the carbon shoe 1 firmly.

A sensing element 30 (shown in FIG. 4A) can be located in the spaceabove the wall 17, which sensing element detects the mechanical behaviorof the shoe (oscillations, shocks etc.). In this way, it is possible totest various aspects: during normal operation, the holder will execute aspecific oscillation. A deviation from this oscillation occurs when, forexample, the carbon shoe has defects such as cracks, delaminations orfractures. Defects in the overhead line and, to a certain extent,problems in the track bed, can also be proven.

FIG. 5 shows a bent spring 18 with opposite edges 19. The spring isprovided with transverse slots 20. A hole 21 is located at the end ofthe spring 18. A hook can be engaged in said hole 21 and the spring canthen be pulled out. Two dashed lines 22 indicate an alternative: theedges could be formed in such a manner for the purpose of pushing thespring on more easily.

FIGS. 6 and 7 show an embodiment before and after assembly. The holderis composed of, for example, aluminum.

The parts, namely the holder and the carbon shoe, can, naturally, alsobe bonded or soldered to one another.

A further embodiment of the invention (See FIGS. 8 and 9) is for thespring 22, apart from its central region, to form an open figure in thetransverse direction of the shoe, which figure is curved on one side,has mutually opposite edges, grips the second webs and presses themagainst one another and, in its central region, for the spring to havean upwardly projecting bulge 25, which presses a contact strip 36, whichis inserted between the carbon shoe 34 and the

I claim:
 1. A current collector holder for a carbon shoe, which bearsagainst a contact wire, for electrically driven vehicles, which holderhas two first webs, which project away from the shoe and are arrangedunderneath said shoe, a spring system separable from said holder beingprovided which presses each of the second webs relative to one anotherfor pressing the first webs against the foot region of the shoe, whereina spring is provided as the spring system, which spring extendsuniformly in a longitudinal direction of the shoe, bears with itslongitudinal region against the second webs, and in this way transmitsits spring force, which acts in a direction transverse to the shoe, tothe second webs for exerting forces continuously over the length of saidshoe.
 2. The holder as claimed in claim 1, wherein the spring forms anopen figure in the transverse direction of the shoe, which figure iscurved in one direction, has two mutually opposite edges, grips thesecond webs and presses them against one another.
 3. The holder asclaimed in claim 2, wherein the spring has transverse slots which endshortly in front of the edges.
 4. The holder as claimed in claim 1,wherein the spring has holes at its ends.
 5. The holder as claimed inclaim 1, wherein the spring is a leaf spring which is slightly curved ina direction transverse to the shoe, and said spring is arranged betweenthe second webs and exerts a force thereon for pressing said second websin a relative direction apart from each other.
 6. The holder as claimedin claim 5, wherein the second webs are short pieces in the longitudinaldirection, which short pieces are connected to the first webs on theright and left alternately and interlock.
 7. The holder as claimed inclaim 1, wherein the spring forms a closed figure, in the transversedirection of the shoe, which figure is curved in one direction, isarranged between the second webs and presses the latter apart.
 8. Theholder as claimed in claim 7, wherein the spring is hollow.
 9. Theholder as claimed in claim 8, wherein an outer wall of the spring iselastic, and said holder comprising means for introducing compressed gasin a controlled manner into said spring.
 10. The holder as claimed inclaim 7, wherein the spring is solid internally and is composed ofrelatively strongly elastic material.
 11. The holder as claimed in claim7, wherein the second webs are short pieces in the longitudinaldirection, which short pieces are connected to the first webs on theright and left alternately and interlock.
 12. The holder as claimed inclaim 1, wherein the spring is composed of spring steel.
 13. The holderas claimed in claim 1, wherein the first webs are connected to oneanother via a wall, which is arranged underneath the second webs. 14.The holder as claimed in claim 13, wherein a sensing element whichrecords the mechanical oscillations of the holder is located in thespace above the wall.
 15. The holder as claimed in claim 14, wherein twosprings are provided, between which the sensing element is located. 16.The holder as claimed in claim 1, wherein the second webs have laterallyprojecting shoulders at their free ends, behind which shoulders thespring engages.
 17. The holder as claimed in claim 1, wherein, in thelongitudinal direction of the shoe, the spring comprises a plurality ofpieces which are adjacent to one another.
 18. The holder as claimed inclaim 1, wherein a sensing element which records the mechanicaloscillations of the holder is located thereon.
 19. The holder as claimedin claim 1, wherein, apart from its central region, the spring forms anopen figure in the transverse direction of the shoe, which figure iscurved in one direction, has mutually opposite edges, grips the secondwebs and presses them against one another, and wherein, in its centralregion, the spring has an upwardly projecting bulge which presses acontract strip, which is inserted between the carbon shoe and theholder, against the carbon shoe.